This application claims the priority of Austrian Patent Application Ser. No. A 367/98, filed Mar. 3, 1998, the subject matter of which is incorporated herein by reference.
The present invention relates, in general, to a film camera and, more particularly to a film camera of a type having a device for recording information data, e.g. a combination of characters and/or digits, onto the film inside the film camera by exposing the film over a predetermined time period by means of an optical display element controlled by an activator.
Film cameras of this type have been in use for some time and permit recordation of synchronizing data onto the film for further processing of the film. Originally, the film industry utilized the ubiquitously known clapper boards for synchronization of image and sound.
Another proposal teaches to record synchronizing data onto the film prior to filming a film sequence, by exposing the film over a number of cadres with the synchronizing information by means of a display element built into the film camera. With these types of film cameras, the information or part thereof, normally recorded on the clapper boards, such as date, scene number or the like, is recorded in the middle of the film. After developing the film negative, the sound and image tracks can then be synchronized on the cutting table. A drawback of this procedure is the inability to infer any time-dependent reference value from the fixed character and/or number combination for use in a fully automated finishing operation of the film.
It is also known to record time-dependent synchronizing data on a separate exposure track during the entire run of the film by use of complicated auxiliary devices which are of complicated structure to realize such a projection. This results not only in high costs but requires use of significant portions of the film.
It is thus an object of the present invention to provide an improved film camera, obviating the afore-stated drawbacks.
In particular, it is an object of the present invention to provide an improved film camera which permits recordation of time information, in addition to other information, onto the film through direct exposure, without encountering any substantial loss of film material.
It is yet another object of the invention to provide a process for synchronization of a filmed sequence with the sound track by using a film camera according to the invention.
These objects, and others which will become apparent hereinafter, are attained in accordance with the present invention by providing an activator, an optical display element operated by the activator for exposing a film to form first data thereon relating to film information, and a time code generator operatively connected to the optical display element for exposing the film, cadre-by-cadre, via the optical display element to form time information, such as actual time, or time elapsed from a set zero point, or other time information, e.g. a running cadre number, thereon in directly readable or coded form.
The desired information can be recorded at the commencement of the film by placing the information centrally on the cadre, with the time code information being exposed onto each of the cadres. Recording this data onto several cadres at the start of the film suffices to create a time frame for later synchronizing the film images to the sound track during operation. The display element can thus not only provide conventional information, such as date or scene number, but also current time information so that several image cadres can be recorded with actual running time or cadre pattern.
According to another feature of the present invention, the time code generator is part of an information unit which is designed as an external module for use with the camera. Thus, the information unit can be separated from the camera, while the desired information to be exposed onto the film can be adjusted, and the time code generator can be calibrated.
To date, in order to cover the image cadre during the exposure of a film, relatively complex and costly mechanical devices were used which included a controllable cover flap and were relatively prone to failure so that situations arose in which light which enters through the camera objective overlaps the exposure of the film by the display element. This drawback can now be eliminated by providing a rotary shutter which deflects light entering the camera objective into the viewfinder when rotated by one half revolution, while allowing a passage of light to an image window when rotated by another half revolution. Suitably, the activator includes a shutter control unit for controlling the rotary shutter drive by which the rotary shutter is retained in a stop position so as to cover the image window when the film is exposed by light emanating from the optical display element. While recording time information from the optical display element onto the film, the image window is thus precisely and reliably covered.
The rotary shutter thus allows light entering through the camera objective to pass alternately during one half revolution to the viewfinder, and during another half revolution to the image window for exposure of the film. When the film transport is stopped, the rotary shutter drive is electronically so moved that the rotary shutter covers at the stop position the image window, thereby providing an unobstructed view from the viewfinder through the camera objective. Thus, when operating the activator of the film camera according to the present invention for realizing an exposure of the film by light emitted from the optical display element, the rotary shutter is previously moved into its stop position or left there to thereby reliably cover the image window. As a consequence of the precisely controllable movement of the rotary shutter, a complete coverage of the image window is assured so as to effectively avoid any overexposure which could potentially render the synchronizing information illegible. After recording the desired information onto the several cadres of the film, the process is terminated by deactivating the activator unit, while the rotary shutter is simultaneously rotated automatically in synchronism with the film transport mechanism.
According to another feature of the present invention, an exposure window, preferably of circular configuration is provided, which is offset by several cadre lengths from the image window in direction of the film transport, and through which the information indicated on the optical display element is projected onto the intermittently advancing film. Arranging the exposure window in this way, permits the recording of information onto the film away from the image window through separate exposure.
When operating the activator, the optical display element lights up with the information to be recorded precisely at the moment when the film, which passes the exposure window step-by-step, remains in the resting position between the steps. Thus, the activator and the film transport are suitably synchronized to one another.
In accordance with a further feature of the present invention, the optical display element may be designed as an active optical display element, preferably a multidigit LED display element for display of the information to be recorded onto the film. This type of LED can display the information to be recorded onto the film in random form. Other optical displays of known type that can produce suitable exposure onto a film cadre may also be utilized.
In accordance with still another feature of the present invention, a projection lens is provided in proximity to the optical display element in order to produce as clear an image as possible of the light emitted from the optical display element and projectable through the exposure window onto the film. In case of spatial constraints, a diverting prism may be interposed between the exposure window and the projection lens.
Synchronization of the image and sound tracks is of particular importance in this context and requires that the time intervals of both, image and sound, will match. For this purpose, the time code generator may thus be calibrated by a suitable time calibration unit, preferably a portable time calibration unit.
The present invention further relates to a process for recording information onto a film through exposure by using a film camera according to the present invention, whereby, it is an object of the present invention to allow recordation of time information onto a film for subsequent synchronization, without loss of any significant film material.
In accordance with the present invention, this object is attained by exposing the film, cadre-by-cadre, to form desired information thereon, such as actual time, or time elapsing from a predetermined zero point, and/or other time-dependent data, such as running cadre number, in directly readable or in coded form. Thus, time information is recorded before the start of the actual filming directly on the film and subsequently can be read during finishing procedure and internally processed by the automated processing machine.
According to another feature of the present invention, the rotary shutter can be held in place for a predetermined time period in a position covering the image window during advance of the film, cadre-by-cadre, past the image window, while the film is exposed, cadre-by-cadre, by light emitted from the optical display element. The optical display element only lights up during moments when the film, which passes intermittently past the exposure window, is held briefly in place, whereupon the next image cadre is transported in front of the exposure window, thereby realizing a precise and reliable covering of the image window for protection against incident light through the objective so as to eliminate any overexposure of information recorded by the optical display element.
According to yet another feature of the present invention, after conclusion of exposure through the display element onto the film, the rotary shutter is again rotated and synchronized with the speed of the film transport. As soon as rotary shutter and film transport speed are again synchronized, the actual film exposure may commence.
The present invention further relates to a method for synchronizing a film sequence with a sound recording by using a film camera according to the present invention, whereby it is an object to provide such a method which allows an automated processing of synchronization data in a simple manner.
In accordance with the present invention, this object is attained by providing a recordation device for exposing a film at the start of a film recordation by to form time information thereon in directly readable or machine-readable coded form on the film, developing a negative of the film, and scanning, and if necessary decoding, the time information contained in single frames on the film by a reading unit, preferably a laser scanner.
In this manner, it is possible to automatically transpose the film onto a videotape. The recorded data which is either in machine-readable code or in directly readable form, is read by means of an optical scanner, if necessary decoded, and converted in suitable form onto the videotape, whereby the correct time in relation to the sound track is automatically matched. The videotape can then be used to process the film in a fully automated manner, particularly the cutting of the film, whereby cadres to be added or to be removed are easily identified by the available time information.
According to a further feature of the present invention, when transferring the image information from the film onto the videotape, the content of the time information of each single film frame is recorded onto the time code track associated to each single frame of the videotape, and the synchronized time information is associated to each successive video image.
As soon as the film is processed completely into its electronic form, the processing information is used to process the original film negative precisely according to the recorded electronic cutting information. This process has the advantage that the very sensitive film negative can be finalized in one processing step, whereas to date, alternately editing and cutting had to be done painstakingly by manual work for each film sequence.